1. Technical Field
The present invention relates to a maintenance unit that maintains a liquid ejecting head for ejecting liquid and a liquid ejecting apparatus including the maintenance unit.
2. Related Art
In general, a liquid ejecting apparatus including a liquid ejecting head for ejecting liquid onto an ejection target member to form an image and the like includes a maintenance unit for maintaining ejection performance to eject liquid from the liquid ejecting head properly (for example, see JP-A-2012-121296).
The maintenance unit includes a plurality of maintenance functions normally. That is to say, the liquid ejection performance of the liquid ejecting head is maintained by operating various functional components for maintaining the liquid ejecting head. For example, when liquid having increased viscosity or liquid in which foreign matters are mixed is present in nozzles, a suction cap is made to abut against the liquid ejecting head so as to cover the openings of the nozzles. Then, a suction pump is operated to suck the liquid having the increased viscosity from the nozzles. With this, the ejection performance is recovered such that the liquid can be ejected through the openings of the nozzles properly. Further, unnecessary liquid attached to the openings of the nozzles is wiped away with movement of a wiping member.
In the liquid ejecting apparatus, the liquid ejecting head is left in a state where the liquid is not ejected through the nozzles for a long period of time when a state where an image is not formed on the ejection target member lasts long. In the liquid ejecting head being left in such state, in order to suppress drying and increase in the viscosity of the liquid in the nozzles which are provided on the liquid ejecting head and through which the liquid is ejected, a leaving cap (cap member) for covering the nozzles so as to surround them is made to abut against the nozzle surface of the liquid ejecting head. Further, a space including the nozzles, which is covered by the abutting leaving cap, is made to communicate with the air through an air communication hole provided in the leaving cap so as to suppress evaporation of the liquid in the liquid ejecting head into the air (into the atmosphere) from the nozzles.
The suction cap and the wiping member are easy to be contaminated because they suck and wipe away a large amount of liquid. Accordingly, a configuration capable of exchanging the suction cap and the wiping member easily is employed in the maintenance unit. On the other hand, the frequency that ink attaches to the leaving cap covering the nozzles is low. Therefore, the configuration capable of exchanging the leaving cap easily is not employed in the maintenance unit in many cases. For example, in the case of detaching the leaving cap, another constituent component of the maintenance unit is required to be detached.
However, for example, if ink remains on the nozzle surface frequently, the frequency that the ink attaches to the leaving cap is increased when the leaving cap (cap member) abuts against the nozzle surface of the liquid ejecting head. When the attached ink reaches the air communication hole and is solidified, it is difficult for the leaving cap to cover the nozzles without breaking menisci formed in the nozzles, resulting in increase in the exchange frequency of the leaving cap. In this case, there arises a problem that the leaving cap (cap member) cannot be exchanged easily.
The above-mentioned circumstances are generally common to the maintenance units that have the cap member and maintain the liquid ejecting head having the nozzle surface in which the nozzles for ejecting liquid onto the ejection target member are formed.